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1TB Blu-Ray Compatible Optical Disc Announced
red_dragon writes "An article on The Register tells the news of an announcement of a new 1TB optical drive and disc that will be backwardly compatible with Blu-ray discs. The technology, developed by Call/Recall in partnership with Nichia, uses a rhodamine-type dye in a 200+-layer recording medium that gives off light when excited by a laser beam, along with a single fluid-filled lens to read multiple layers by varying the amount of fluid to change the focal length. The technology is designed to work with Nichia's blue-violet laser diodes, which are already used in Blu-ray drives."
nope, its most likely layer not laser.
Nope.
For a pressed DVD, a master is etched, and is then used to physically press the pits into the substrate. The depth of these pits (1/4 wavelength) causes destructive interference when the beam hits a pit, and constructive interference when it hits a land. (1/4 wavelength in + 1/4 wavelength out = 1/2 wavelength out of phase with the rest of the beam reflecting off the surrounding substrate)
This is pretty much permanent, provided your media doesn't disintegrate.
For a burned DVD, a photosensitive dye is activated by the writing laser. This activated dye simply absorbs the beam that hits a "pit", while the unactivated dye allows the beam to reflect off the substrate behind, when it hits a "land".
Over time, this dye can degrade such that the unactivated dye slowly activates (either spontaneously or in reaction to ambient light), or that the activated dye slowly deactivates for the same reason (much like a photo left in the sun).
One of the reasons that "archive quality" disks are more expensive is that they use a higher quality dye which takes longer to degrade.
I guess we've finally found something that takes more than one disc!
(T>t && O(n)--) == sqrt(666)
It was done long ago during the twilight of CD only drive...
See...
http://everything2.com/e2node/TrueX
http://en.wikipedia.org/wiki/CD-ROM#Transfer_rates
http://www.halfbakery.com/idea/Multiheaded_20CD-ROM
I believe the main issues were reliability, cost and lack of noticeable speed gains when using the CD-ROM in common tasks. Although there isn't much to be found (or said) about them anymore. It would seem the increased density of today's optical media put a damper on the need for increased spindle speeds making multiple lasers an unattractive way to boost speeds.
Also if I remember correctly they were entering a market at a time when CD-R/RW drives were becoming more cost competitive.
I'm sick of following my dreams. I'm just going to ask where they're goin' and hook up with 'em later.
CD-R discs flake. DVD-R discs have the metal layer between two layers of plastic, so they can't flake (unless you mean the label paint). They can oxidize, but not flake. As a result, DVD-R should be much less susceptible to accidental damage than CD-R media.
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